1. Field of the Invention
The present invention relates to a lens unit for photography capable of remote/local control to control focus and wobbling mechanisms by power, and a camera system using it.
The lens unit of the present invention solves the problem wherein when a lens unit with a digital serial interface was connected to a camera unit without the interface, there arose the problem that setting was disabled of a mode of the lens unit from the side of the camera unit.
2. Related Background Art
The focus control of the lens unit for photography is effected either by manipulating a focus ring directly by hand or by power-driving a focus mechanism of the lens unit by use of such an actuator as a motor. For power-driving of the focus mechanism, there are a mode (local mode) in which the focus control is carried out based on a control signal outputted in response to manipulation of a demand incorporated in or connected to the lens unit and a mode (remote mode) in which the focus control is carried out based on a control signal from a focus operating means or an autofocus means of a TV camera unit connected to the lens unit or based on a control signal outputted in response to manipulation of a demand on a camera control unit CCU connected to the TV camera unit.
The lens unit has a changeover function for changeover between the local mode and the remote mode and a changeover instruction of mode is given from a mode changeover switch provided in the camera unit or in the CCU to the lens unit.
The changeover function between these remote/local modes is provided as an interface between a large-size TV camera unit, used conventionally in studios etc., and the lens unit. The interface between the large TV camera unit and the lens unit is constructed as a system of so-called parallel connection in which each connector pin is assigned to a signal of one function, using a large connector with many pins. In this system a remote/local changeover signal is sent to the lens unit by use of a dedicated wire through one connector pin. Under this setup, the remote/local signal from the CCU or from the camera unit is transmitted to the photographing lens at the same time as turning on of power, so that either the remote mode or the local mode is set instantly in the lens unit.
On the other hand, in the case of a small-size TV camera unit and a lens unit for this small TV camera, they are connected in parallel by a small connector with less pins. The small TV camera units have been used in such circumstances that a cameraman carried the camera system on the shoulder outdoor to take a picture by himself, and there was no need for the remote mode. Therefore, the conventional interfaces were not provided with the changeover function between the remote mode and the local mode.
However, desires are increasing recently for the autofocus system for outdoor photography as well, and thus the autofocus function is also demanded for the small TV camera units. This raised the necessity for exchange of much information between the small TV camera unit with the autofocus function, and the lens unit. The parallel interface of the small connector is, however, short of connector pins, and thus a digital serial interface is also added to the existing parallel interface, whereby exchange of much information is made by digital signals. Further, the digital serial interface is provided with the changeover function between the remote mode and the local mode of focusing.
At present still many users also possess the small TV camera units without the serial interface and have desires for using the lens unit with the AF function having the serial interface, in a mounted state on the small TV camera unit without the serial interface, though not using the AF function.
When the lens unit with the digital serial interface is mounted on the small TV camera unit without the serial interface, there arises, however, a problem that an instruction of setting of either the remote mode or the local mode cannot be sent from the small TV camera unit to the lens unit, so that the focus operation of the lens unit is disabled.